Electron Microscopic Observation on Cholesterol Granuloma of the Middle Ear

Abstract

Cholesterol granuloma consisted of various kinds of granulation tissue cells. Short or large cholesterol needles, which appeared as empty spaces in the sections were scattered in the granulation tissue, frequently in a pool of red blood corpuscles. They were also noted in and/or adjacent the giant cells. In the cytoplasma of giant cells the cholesterol needles were surrounded by mitochondria and lysosomes, and they were partly covered with some darkly stained lipid-like amorphous material. An indented nucleus spiked by a cholesterol needle was sometimes detected in the multinucleated giant cell. Since the giant cells in cholesterol granuloma possess similar ultrastructural properties to actively phagocytic histiocytes, they may play an active role in the absorption of cholesterol crystals.